Method of making slit pins having continuously bevelled ends



A. RAFTER April 10, 1956 METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLYBEVELLED ENDS 2 Sheets-Sheet 1 Filed Sept. v2'7, 1952 IN V EN TOR.

ATTORNEY April 10, 1956 A. RAFTER 2,741,023

METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLY BEVELLED ENDS Filed Sepi.27, 1952 2 Sheets-Sheet 2 J INVENTOR.

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United States Patent METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLYBEVELLED ENDS Albert Rafter, Glen Ridge, N. J., assignor, by mesneassignments, toStandard Pressed Steel Co., Jenkintown, Pa., acorporation of Pennsylvania This invention relates to the art of makinglongitudinally slit pins which are used in many industrial and otherapplicationsfor example, as bearings in hinges and other aperturedparts, as shown, for example, in German Patent No. 510,788, of October28, 1930. Tubes with tapered ends to facilitate their insertion intoapertures are shown in patents such as Patent No. 1,889,324 of November29, 1932. Other patents in the art--for example, U. S. Patent No;653,900-show the idea of forming continuous rings from initially fiatstrips of material grooved in fiat form and then forced into circularform.

However, methods heretofore proposed for the forming of longitudinallyslit tubes with bevelled ends from flat stock material have beencumbersome and wasteful and have not been satisfactory for practicalproduction purposes. 1

This invention provides a method for the production of uniformlyaccurate, longitudinally slit tubes with continuously bevelled ends frominitially flat stock material,

in a practical and efficient manner.

It is essential that the bevelled or other ends-formed on such tubes becontinuous up to the very edges of the slits. The method of thisinvention enables continuous production of-pins of uniform accuracy,continuously bevelled along their ends and to thevery edges of theirslits.

The accompanying drawings illustrate practical embodiments of theinvention; it will be apparent to those skilled in the art that pursuantto the teachings of the present disclosure, many additions andmodifications may be made within the spirit and scope of the invention.All of such modifications which utilize the principlesof the inventionas set forthherein and come Withinthe terms of the appended claims shallbe deemed to be within thewpurview and scope of this invention.

in the drawings:

Fig. 1 is a schematic view of the step of preforming the blankto anintermediate stage, pursuant to this invention, I t

Fig. 2 is a vertical sectional, partly perspective of the blank, takenon line 2 2of Fig. 1 V i Fig. 3 is a view of the blank pre-formed atline 3-3 of Fig. 1,

Fig. 4 is a vertical sectional view taken on line 4-4 of Fig. 5,

Fig. 5 is an elevational view taken on line 5-5 of Fig. 4,

Fig. 6 is a perspective View of the punch and anvil members shown inFigs. 4 and 5,

Fig. 7 is an enlarged fragmentary plan view of connected tubespreformedand grooved pursuant to the invention,

Fig. 8 is a vertical sectional view, taken on line 8-8 of Fig. 7,

Fig. 9 is a schematic view illustrating a rolling mechanism which may beused to complete the pins from the preformed state indicated in Figs. 7and 8, to the final form indicated in Figs. 11 and 12.

Fig. 10 is a schematic view of the final step of separation of connectedtubes.

Fig. 11 is a fragmentary plan view of a pin completed pursuant to thisinvention, and

Fig. 12 is an end elevational view thereof, taken on line 12-12 of Fig.11.

The method of this invention is designed for fabrication of pins such asshown in Figs. 11 and 12 from flat blanks of material as indicated at 10in Figs. 1 and 2. These blanks of material may be, for example, ofcontinuous strip form, as shown in Fig. 1, fed from a suitable roll orother source of supply.

Pursuant to the invention, the flat blank of material is preformed fromthe original flat form thereof shown in Fig. 2 to the form shown in Fig.3 by forming the longitudinal edges 11, 12 of said blank into arcuatemarginal portions to impart a generally C-shaped transversecrosssection, by passing the blank 10 between dies or rolls, such as,for example, the rolls 15, 16 in Fig. 1.

The blank 10 is then passed beneath a punch 20 or other impressingmember. The punch 26 is provided with an upstanding edge 21 which istransversely of U-shaped outline and which is provided with a chamferedface 23 (see Fig. 4), whereby, when said punch is brought down onto thepreformed blank of Fig. 3 passed therebeneath with the marginal edges13, 14 directed away from the punch, a transversely continuous chamferedgroove 17 (Fig. 8) will be impressed continuously onto the top andmarginal edges of the blank and to the very extremities of the marginaledges 13', 14', see Fig. 8. The parts are so proportioned that thecontour of the punch conforms to that of the preformed (Fig. 3) blank sothat the impressed chamfer groove 17 will be continuous along the blankat precisely that point thereon which is intended to be the chamferedend in the completed pin (Fig. 11). In the operation of impressing thechamfer groove 17 onto the preformed pin, punch 24 is caused to movepartly through the blank; the groove 17 will correspondingly extend onlypartly therethrough (Fig. 8). Thus, the blank is provided at one and thesame point with a chamfer groove 17 and (thereby) with a portion ofreduced thickness.

The step above described, wherein the punch impresses the blank with thetransversely continuous chamfer groove 17, will be repeated as the blankmoves beneath punch 24 (as in direction 28 of Fig. 4) at those pointsalong the blank which have been predetermined to divide it into pins ofthe desired length. As shown in Fig. 4, the step of impressing thechamfer groove 17 into the preformed blank may be performed at a stationin the machine or apparatus at which an anvil 38 is disposed beneathpunch section 24 and in registry therewith. The anvil has an upstandingface 31 of complementary outline to that of the cavity 22 of the punchbut of predetermined lesser dimensions, so that the preformed blank illof Fig. 3 will be smoothly supported upon the upstanding face 31 of theanvil 30. In practice, the blank 10 may be a long, continuous strip, fedfrom reels or in suitable lengths or sections through the rolls 15', inor other mechanism for providing the fiat blank 18 with the arcuatemarginal edges 13, 14. The blank so preformed is then passed under thepunch to impress the same, at each cycle of descent of the punch, withthe chamfer groove 17 and reduced portion 18. The blank is then passedthrough suitable mechanism, as, for example, forming rolls 26, 27, 28,29 of Fig. 9, which will form the blank, intermediate its arcuatemarginal edges 13, 14 into the desired final circular or other form andto dispose said edges in close parallel spaced relation as shown in Fig.12. As shown in Fig. 10 in the final step, the blank is advanced to aposition at which a pressure or stress-exerting member 32 will engagethe blank to fracture it at the point 18 thereof which marks the 'theaxis and break cleanly at said'point.

end of the chamfer groove17 and the location of reduced portion -18. InFig. there is shown'an impact member 32 which descends'onto the tube ator adjacent to the weakened point 18' causing the tube to flex along Thespecific arrangement shown in Fig. 10 or other suitable means to attainthis-end maybe used for that final step. If desired, the pin may be,passedthrough a suitable apertured member 33 which will stabilize thesame in the step of fracturing it at its weakened points 18'. Member 32may be on the order of a hammer or striker moving downwardly ontotheblank as the latter moves through the machine, or the blank'may beotherwise subjected to stress and strain at the weakened points 18thereof by use of other tools or means adapted to that end.

It has been found, in practice, that, pursuant to the method abovedescribed, tubes may be manufactured with uniform accuracy. The tubesbreak at the points '18 cleanly and without roughened edges.

Pursuant to the present invention spring pins of uniform cross-section,as indicated at 35 in Fig. 12 and with slits or openings'36 and bevelledends continuous to the very edges of said slits may be made. This typeof pin is particularly desirable where it is necessary for the pin tofiex to absorb stresses, and permits it to be slightly contracted forinsertion and to expand to exert continual tension against the walls ofthe opening uniformly throughout the length of the pin. The pin may beheat-treated so that it may be used over and over again due to itsinclination to resume its original diameter, indicated in Fig. 12.

The above described bevelled face 23 of the punch 20 may be duplicatedas at 23', said "chamfered faces 23, 23' being of such predeterminedangle as may be desired for the chamfered groove 17, thus providing thepunch with an edge '21'of V cross section. In some instances, as, forexample, where it is desired that the opposite ends of the pins shallnot be correspondingly bevelled-for example, where it is desired thatone end of the pin shall have a chamfer groove of greater angle than theother, this objective may be attained by correspondingly varying theangles of the chamfer faces 23, 23 of the punch 20, which provide thechamfer grooves 17, 17' (Fig. 7). The punch may be formed of .sections24, 25 secured together or used independently depending on theparticular application at hand. By timing the speed of movement orfeeding of the blank through the apparatus relative to the cycles ofdescent of the punch, the length of the finished pins 27 may bepredetermined.

The arcuate marginal edges 13, 14 may be preformed on the blank at thatstep of the method which is illustrated in Fig. 3 to constitute arcs orslit ends of the final form 35 (Fig. 12) into which the tube isto bemade or to constitute an intermediate between theflat original crosssection form of the blank shown in Fig. 2 and the final cross section ofthe pin indicated in Fig. .12, the final completion of the desired crosssection being attained in the step of rolling or otherwise completingcross sectionally the form of the pin as by use of the Fig. '9 "or otherforming apparatus.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. The method of forming a fiat non-bevelled metal blank having spacedparallelmargins into a longitudinal slit pin with a continuouslybevelled end, which comprises first forming the longitudinal margins ofsaid flat blank into arcs directed in the plane of the blank having atZ-shaped transverse cross-section, then moving a punch member having anupstanding edge of the V shaped cross-section, transversely of U-shapedoutline generally corresponding to .the so preformed blank incross-section onto the blank and partly thereinto, to thus impress thesaid blank with a continuous transverse V recess from edge to edge,while the blank has said C-shaped transverse cross-section, subsequentlyforming the blank to a final generally tubular form, wherein the recessfollows the contour of the blank as a continuous recess from edge toedge thereof, and breaking said blank medially of said V to define asmooth bevel continuous from edge to edge thereof.

2. The method of forming a flat non-bevelled metal blank having spacedparallel margins into a longitudinal slit pin with a continuouslybevelled end, which comprises first forming the longitudinal margins ofsaid fiat blank into arcs directed in the plane of the blank having aC-shaped transverse cross-section, thereafter disposing said blank abovean anvil and then moving a punch member having an upstanding edge of theV-shaped cross-section, transversely of U-shaped outline generallycorresponding to the so preformed blank in cross-section'onto theblankand partly thereinto, to thus impress the said blank with acontinuous transverse V recess from edge to edge, while the blank hassaid O-shaped transverse cross-section, said 'anvil having a face ofC-shaped outline corresponding to that of the upstanding edge of thepunch, supporting the blank while the punch is impressing the recessthereon, subsequently forming the blank to a final generally tubularform, wherein the recess follows the contour of the blank as acontinuous recess from edge to edge thereof, and breaking said blankmedially of said V to define a smooth bevel continuous from edge to edgethereof.

References Cited in thefile of this patent UNITED STATES PATENTS 653,902Bray July 17, 1900 1,366,063 Culhane Jan. 18, 1921 1,756,403 ThomsonApr. 29, 1930 1,924,230 Davis Aug. 29, 1933 1,931,162 Kranz Oct. 17,1933 2,222,842 Humphrey Nov. 26, 1940 2,248,172 Pruckner July 8, 19412,582,063 Zitzewitz Jan. 8, '1952 2,630,174 Poteet Mar. 3, 1953

